Sathyamangalam (also known as Sathy) is a small city and taluk in Erode district in the Indian state of Tamil Nadu. It lies on both banks of the Bhavani River, a tributary of the Kaveri in the foothills of the Western Ghats. It is about 70 km from Coimbatore city. Sathyamangalam was formerly part of Coimbatore District, but became part of Erode District when the district was constituted in 1979.